Question: What Columbia President attended the school that was the employer of the person who wrote the significance of the frontier in american history?
Context: Document 1: The Significance of the Frontier in American History: ``The Significance of the Frontier in American History ''is a seminal essay by the American historian Frederick Jackson Turner which advanced the Frontier Thesis of American history. It was presented to a special meeting of the American Historical Association at the World's Columbian Exposition in Chicago, Illinois in 1893, and published later that year first in Proceedings of the State Historical Society of Wisconsin, then in the Annual Report of the American Historical Association. It has been subsequently reprinted and anthologized many times, and was incorporated into Turner's 1921 book, The Frontier in American History, as Chapter I.
Document 2: Frederick Jackson Turner: Frederick Jackson Turner (November 14, 1861 – March 14, 1932) was an American historian in the early 20th century, based at the University of Wisconsin until 1910, and then at Harvard. He was primarily known for his “Frontier Thesis.” He trained many PhDs who came to occupy prominent places in the history profession. He promoted interdisciplinary and quantitative methods, often with a focus on the Midwest. He is best known for his essay "The Significance of the Frontier in American History", whose ideas formed the Frontier Thesis. He argued that the moving western frontier shaped American democracy and the American character from the colonial era until 1890. He is also known for his theories of geographical sectionalism. In recent years historians and academics have argued strenuously over Turner's work; all agree that the Frontier Thesis has had an enormous impact on historical scholarship and the American soul.
Document 3: Harvard University: Politics: U.N. Secretary General Ban Ki-moon; American political leaders John Hancock, John Adams, John Quincy Adams, Rutherford B. Hayes, Theodore Roosevelt, Franklin D. Roosevelt, John F. Kennedy, Al Gore, George W. Bush and Barack Obama; Chilean President Sebastián Piñera; Colombian President Juan Manuel Santos; Costa Rican President José María Figueres; Mexican Presidents Felipe Calderón, Carlos Salinas de Gortari and Miguel de la Madrid; Mongolian President Tsakhiagiin Elbegdorj; Peruvian President Alejandro Toledo; Taiwanese President Ma Ying-jeou; Canadian Governor General David Lloyd Johnston; Indian Member of Parliament Jayant Sinha; Albanian Prime Minister Fan S. Noli; Canadian Prime Ministers Mackenzie King and Pierre Trudeau; Greek Prime Minister Antonis Samaras; Israeli Prime Minister Benjamin Netanyahu; former Pakistani Prime Minister Benazir Bhutto; U. S. Secretary of Housing and Urban Development Shaun Donovan; Canadian political leader Michael Ignatieff; Pakistani Members of Provincial Assembly Murtaza Bhutto and Sanam Bhutto; Bangladesh Minister of Finance Abul Maal Abdul Muhith; President of Puntland Abdiweli Mohamed Ali; U.S. Ambassador to the European Union Anthony Luzzatto Gardner.
Answer: Juan Manuel Santos
Reasoning steps: who wrote the significance of the frontier in american history Answer: Frederick Jackson Turner
Frederick Jackson Turner >> employer Answer: Harvard
What Columbia President went to Harvard ? Answer: Juan Manuel Santos